Knowledge Skill Expanded Uses

[Fax Celestis]

Okay, so I'm looking for class features and feats (and other things too, if applicable) that are powered by your Knowledge skills: either your ranks in them or a roll, so Knowledge Devotion is in, Bardic Knowledge is in, feats like Research and Education are in...

Classes
Archivist: Dark Knowledge provides scaling benefits vs opponents based on your relevant Knowledge skill - HoH
Bard: Bardic Knowledge, all Knowledges as class skills, Lore - Core
Bardic Sage: as Bard, but +2 to Lore in exchange for different saves (good Will, poor Ref and Fort). - UA
Cloistered Cleric: Lore, Knowledge domain - UA
Rilkan Rogue: Bardic Knowledge - MoI


Prestige Classes

Ebon Scholar: 9/10 casting, basically like Loremaster with a different (and in some instances, better) list of options, Lore. Entry: ECL 10, arcane only - SGoS
Loredelver: 9/10 casting, stacking bardic knowledge. Entry: ECL 8, Illumian, arcane magic, trapfinding - RoD
Loremaster: 10/10 casting, select from a list of options at most levels based on your Knowledge skills, Lore. Entry: ECL 10, any magic - Core
Paragnostic Apostle: 5/5 casting, select from a list of options based on your Knowledge skills, stacking Lore. Entry: ECL 5, any magic - CCham
Troubadour of Stars: 5/10 casting, Lore. Entry: ECL 9, spontaneous arcane magic, Exalted - BoED


Feats
Aftersight: Rashemi-only. 3/day, make a DC 10 Wis check to have a brief vision and gain a +4 bonus on Lore, Knowledge (History) for 1 minute. - RoF
Ancestral Knowledge: Dwarf-only. Lets you make Knowledge checks untrained, also lets you use Wisdom instead of Intelligence for Knowledge checks. - RoS
Draconic Knowledge: True-dragon-type only. Gives you a Lore ability, mostly related to history and treasure - Draco
Education: Makes all Knowledge skills class skills, +2 to 2 Knowledges of your choice. - ECS
Forbidden Lore: Lore and taint required. Add a bonus based on how tainted you are to Knowledge checks pertaining to Lovecraftian or cthulhoid subjects.
Keeper of Forbidden Lore: +1 bonus per Abyssal Heritor feat to all Knowledge Spellcraft, and Lore checks, Knowledge (Planes) and Spellcraft are always class skills, -2 to Gather Information. - FCI
Knight of Tyr's Holy Judgement: Member of Knights of Holy Judgement only (an Exalted paladin order). Add your Paladin level to Knowledge or Intelligence checks regarding laws. Allows you to make Knowledge checks to discover local law (and specifically, loopholes in the law so you can bring violators to justice) even when you don't know the area or local law. Detect Evil also detects devils on its second round of concentration. +1 sacred to AC vs devils. - CoV
Knowledge Devotion: scaling attack and damage bonuses based upon your relevant Knowledge check. - CCham
Lunatic Insight: Tainted-only. Trained in all Knowledge skills, +2 to initiative and saves vs. mind-affecting. - HoH
Master of Knowledge - +1 on all Knowledge checks. - HoH
Obscure Lore: +4 on Lore checks. - CAdv
Research: adds new options for Knowledge skills for navigating a library or similar. - ECS
Trivial Knowledge: Gnome-only. When making a Knowledge or Lore check, roll twice and take the better result. - RoS
Veteran Knowledge: +5 on Knowledge checks made to gain a strategic advantage - HoB

[Diovid]

Take a look at the Urban Savant from Cityscape. It has an ability similar to the Archivist's Dark Knowledge but potentially much more game-breaking.

Combine it with the Trivial Knowledge feat and various other knowledge-boasting feats and abilities and you have scary knowledgemonkey.

Something like Bardic Sage 4 / Marshal 1 / Dragonfire Adept 1 / Urban Savant 9 / Paragnostic Apostle 5 for example.

Additional feats:

Breadth of Knowledge (Unearthed Arcana)
Dragonic Aura (Dragon Magic)
Draconic Knowledge (Dragon Magic)

[Fax Celestis]

Added some stuff, still working on this. Suggestions welcome.

[Person_Man]

Although this isn't made explicit in the RAW descriptions, many Knowledge Skills cover certain types of creatures. (Religion covers Undead, Nature covers Animals, etc). Thus a player should be able to make an appropriate Knowledge check to discover if it has any immunities/resistances/etc, how to bypass it's damage reduction, if it has any special attacks, etc.

[Ezekiul]

Sacrificing in book of vile darkness, optimized knowledge religion makes it strong.

[Lightlawbliss]

collector of stories skill trick